In recent years, liquid crystal display devices are widely used as a display device of smartphones, tablet computers, vehicle-navigation systems, etc. In general, a liquid crystal display device comprises a liquid crystal display panel and a backlight device overlaid on the rear surface of the liquid crystal display panel and illuminates the liquid crystal display panel. The backlight device includes a reflective layer, a light guide, an optical sheet, a light source unit which irradiates light which enters the light guide. The reflective layer, light guide and optical sheet are stacked one on another. The backlight device further includes a case (bezel) made from a metal plate, which accommodates these members. The light source unit includes a wiring board and a plurality of light sources, for example, light-emitting diodes (LEDs) mounted on the wiring board.
In recent years, as display areas have increased, there has been a continual demand for the frames of liquid crystal display devices to become ever narrower and the liquid crystal display devices to become ever thinner.